This invention relates to simple and inexpensive hand-held, non-motorized, i.e., purely mechanical, do-it-yourself hair trimming or cutting devices, and more particularly to handleless hair trimming/cutting devices, utilizing conventional razor blades safely deployed therein, and operable by a typical combing action.
Relatively simple purely mechanical or non-motorized hair trimming devices which are operable via a regular hair combing action are known to the art. Such a device is found in U.S. Pat. No. 4,441,252, which describes a hair trimming device using conventional double-edged razor blades sandwiched between a base plate and mating capping member, both of which are provided with a pair of oppositely arranged, groups of comb-like teeth of the same configuration. The blade-sandwich unit is removably mountable to the forked distal end of a handle. The forked end has resilient arms which allow the sandwich to be slidably inserted therein to a force-fit locked position.
Such a device, while being simple offers the user no versatility as to operative or combing/cutting interfaces or surfaces for the various different parts of the head, and is clumsy with regard to blade replacement and provides no adjustment factor to counter aging (wear and tear) or user "feel".
Another mechanical/non-motorized hair cutting device, significantly more complex than the foregoing device, is found in U.S. Pat. No. 3,986,258. This arrangement provides a blade interchangeably retained between a blade-support plate and a cover plate, which has a row of teeth of linearly varying length overlapping the blade cutting edge. The two plates are displacable perpendicularly to the cutting edge and relative to each other between a pair of end positions. The device provides a wedge-shaped element proximate the blade cutting edge which increases in thickness extending from the cutting edge to enable the blade to be effectively adjustable to a cutting angle determined by the front ends of the comb-like teeth together with contact of the wedge with the head. A coupling member is disposed on each plate to selectively locate same relative to one another and a spring retains the coupling members, with prestressing, in positive engagement with one another.
In both of the foregoing arrangements, only one configuration of fixed comb-like teeth is provided. In the case of the "258" patent device, the configuration consists of a single row of teeth of consistent tooth spacing, only the length parameter of which teeth varies (in the given case, linearly) from a minimum at the forward operative end to a maximum at the other end of the operative surface, whereby the free ends of the teeth define a line of points which forms an acute angle with the longitudinal axis of the main body and handle of the device. Additionally, blade replacement is a relatively complicated process.
The device of the "252" patent provides a single configuration of teeth consisting of a pair of oppositely arranged rows, the spacing and length of which teeth are consistent, such that the ends of the teeth of each row define the same line of points parallel to and separated the same distance from, though on opposite sides of the longitudinal axis of the body and handle of the device.